The present invention relates generally to the field of engines. More specifically the present invention relates to systems for controlling the speed of engines.
An engine governor is used to help regulate engine speed, which is typically quantified in terms of the revolutions per minute (rpm) of the engine output shaft (e.g., crankshaft). The governor systems operate in one of three configurations: the governor is pneumatically controlled by the air cooling system of the engine, the governor is mechanically controlled by the crankshaft, or the governor senses a rate of electrical pulses of an ignition system of the engine. In each configuration, the engine speed is communicated to a portion of the engine that regulates fuel usage (e.g., throttle assembly), where if the engine is running too slow, fuel flow through the engine is increased, increasing the engine speed—and vice versa.
Typical engine governors experience a phenomenon called “droop,” where a decrease in the engine speed occurs with an increase in loading of the engine. As a result of droop, an engine that is running without load operates at a higher speed than a fully loaded engine. By way of example, such a difference in engine speed may range from about 250 to 500 rpm between an unloaded and fully loaded engine. For example, the engine for a pressure washer may run at about 3750 rpm with no load, and at about 3400 rpm at full load.
The present invention relates generally to the field of carburetor systems. More specifically, the present invention relates to carburetor systems for engines configured to run outdoor power equipment, such as snow throwers.
Snow throwers and other types of outdoor power equipment are typically driven by an internal combustion engine. The engine includes a carburetor, which adds fuel to air flowing through the engine for combustion processes occurring within the engine. The carburetor includes a passageway through which air typically flows from an air cleaner or filter to a combustion chamber of the engine.
Along the passageway, the carburetor includes a venturi section having a constricted area, where the cross-sectional area orthogonal to the flow of air through the carburetor is reduced relative to portions of the passageway before and after the constricted area. The carburetor further includes a nozzle in or near the venturi section that is in fluid communication with fuel.
Constriction of the passageway through the venturi section increases the velocity of air passing through the constricted area, which generates low pressure at the nozzle. The low pressure pulls fuel through the nozzle and into the air. The fuel mixed with the air is then burned in the combustion chamber to power the engine, which in turn drives a crankshaft that powers the auger of the snow thrower.